An experimental stroke model in the rhesus monkey has been developed. The "stroked" animals are being evaluated by x-ray angiography, radionuclide scanning, radionuclide cerebral blood flow determination, radionuclide particles (macroaggregates) transit, Fluorescein angiography, Laser-Doppler velocimetry, microangiography, and autoradiography. The CBF in the experimental infarcted brain is being modified by various physiological, chemical, pharmacological and surgical (revascularization) means. In a collateral experiment various parameters of the cerebral circulation are being studied after production of arterial spasm in the circle of Willis in monkeys. The spasm is cause by total blood - or fractions thereof -introduction within the subarachnoidal space (chiasmatic cistern). Publication: Williams, P.C., Stern, M., Bowen, P.D., Brooks, R.A., Hammock, M.K., Bowman, R.L. and Di Chiro, G.: Mapping of cerebral cortical strokes in rhesus monkeys by laser Doppler spectroscopy. Medical Research Engineering (I presss)